Field of the Invention
Crude extracts of mycobacteria contain many antigens of varying chemical composition. Some of these antigens are probably species specific; others are known to be shared among many species and almost certainly contribute to the antigenic cross reactivity commonly observed with mycobacterial extracts. Fractionation of either mycobacterial culture filtrates or of mycobacterial cell extracts has been employed by many investigators in search of isolated, purified antigens.